The design of a novel, microfluidic chip with an integrated micro peristaltic pump and chambers for DNA amplification is described. This chip contains three reaction chambers stable at 90 • C, 72 • C and 55 • C for PCR amplification, a bi-directional peristaltic pump and optical integrated detection of the droplet. A reactant droplet is to be introduced into the device, pumped back and forth between the chambers by the micro peristaltic pump for sample processing. The static behaviour of the micro pump was modelled theoretically in order to evaluate the optimal dimensions for the pump membranes and to obtain the maximum flow rate. Thermal analysis by the finite element method was performed to optimize the location of the heaters and the temperature uniformity over the three reaction chambers. Transient thermal analysis indicates that the reactant droplet can be heated/cooled in the proposed device in less than 1 s to achieve the desired temperatures.

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Scanning Photo-Induced Impedance Microscopy (SPIM) is an impedance imaging technique that is based on photocurrent measurements at field-effect structures. The material under investigation is deposited onto a semiconductor-insulator substrate. A thin metal film or an electrolyte solution with an immersed electrode serves as the gate contact. A modulated light beam focused into the space charge region of the semiconductor produces a photocurrent, which is directly related to the local impedance of the material. The absolute impedance of a polymer film can be measured by calibrating photocurrents using a known impedance in series with the sample.Depending on the wavelength of light used, charge carriers are not only generated in the focus but also throughout the bulk of the semiconductor. This can have adverse effects on the lateral resolution. Two-photon experiments were carried out to confine charge carrier generation to the space charge layer. The lateral resolution of SPIM is also limited by the lateral diffusion of charge carriers in the semiconductor. This problem can be solved by using thin silicon layers as semiconductor substrates. A resolution of better than 1 m was achieved using silicon on sapphire (SOS) substrates with a 1 m thick silicon layer.

We present a highly sensitive ultra-thin micromachined silicon cantilever beam with an integrated strain gauge on its root for optimizing piezoresistive readout. The mechanical characteristics and electrical readout of the cantilever beam, such as spring constant, resonant frequencies and piezoresistive sensitivity, are theoretically given from the derived formulae or from finite element modeling. The results of characterization show reasonably good agreement between the experimental results and the theoretical values. As one of the applications, for the first time the fabricated silicon cantilever beams have been applied to measure airflow velocity distribution in a steel pipe with an inner diameter of 7.0 mm. The experimental piezoresistive sensitivity ( R/R)/y(0) is in the range of 0.23-2.89 × 10 −6 nm −1 in the beam bending tests, and the experimental flow sensitivity ( R/R)/V gas 2 is in the range of 0.652-4.489 × 10 −5 (m s −1 ) −2 in the airflow velocity tests. The experimental detectable minimum airflow velocity is 7.0 cm s −1 , which is comparable to that of a hot wire anemometer.

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